Vacuum cleaner



`H.A LI'NGENBRINK I 2,091,642

VACUUM CLEANER Aug. 31, 1937.

Filed Feb. 13, '1956 INVENTOR Ipatented Aug. 1937 UNlrElofsTA-TES vacuum vcaminan Hermann Lingenbrink, Newton, Mass., assigner to McManus Engineering Corporation, Cambridge, Mass., a corporation of Massachusetts 'Appucation February 13, 1936', 'serial No. 63,704

In Canada August y10, 1935 2 Claims. u (Cl. {30V- 95) This invention relates to vacuum cleaners and it has for its object to provide a device of that character which, because of its simplicity and compactness in construction, forms a handy im- 5 plement for cleaning lautomobile cushions and the t like, and yet in which its simplicity in construction is obtained without sacrifice to the suction necessary for a thorough cleaning. To that end,

I dispense with the use ofv a fan and motor, such as are customarily employed to-create the suction in such cleaners, and instead I utilize compressed air, commonly available in' garages, as the means for producing the suction.

It has heretofore been proposed to employ a' l5 stream of compressed air directed longitudinally -of an open tube as means for creating suction in apparatus of various sorts, but, so far as I am aware, no such devices have been successfully employed heretofore as vacuum cleaners because of the inability of such devices to suck in ylarge quantities of cleaning air with the force necessary for a thorough cleaning, the high cost of operation involved in the large quantities ofl compressed air consumed, and nally because of the cumbersomeness of such prior structures.

I have found that small quantities of compressed air only need be employed to draw in substantial volumes of cleaning air, withthe desired force, if rthe compressed air be introduced tance alongthe tube, to entrain the surrounding' air, after which, and while the conical air stream is still travelling at a predetermined high velocity, the walls of the tube are converged internally .to shield the stream, whereby to inhibit further entrainment of surrounding air by the stream, While at the same time not materially restricting the longitudinal ilow of the stream. The shield commences at a mouth which is spaced from the `orifice the distance required for the .initial unconfined travel of the stream and the shield continues from the mouth to the outlet end of the tube in a diverging conical flare whichmay. be slightly less than the angle of divergence o f the stream entering the mouth.

' 50 I have found that this combination of small'jet oriiice and spaced shield is not only eective-for utilizing the available compressed air vwithout wasting it, but is also advantageous in that it enablesme to simplify the structure in ways 55 other than bythe mere elimination of the motor and fan. 'I'hus the jet oriice andspaced shield, which are preferably in axial alignment with ,each other, enable me to form the device in the shape of a' short piece of tubing with a nozzle of desired shape atone end anda small dust bag atv 5' its opposite end. Furthermore, the construction of the valve provided for turning on and oi the compressed air which induces the suction, may be 'simplied by operating it from't-he back pressure of the compressed air in .thetube leading to 10 the small jet orice. 1 y

These and further objects and advantages of my invention will appear from a more detaileddescription thereof taken in connection with the, accompanying drawing, in which,-' l5 Fig. 1 is a' side elevation view of the vacuum leaner complete with suction nozzle and' dust gl. Fig. 2 is a plan view of the tube. Fig. 3 is a vertical longitudinal section taken 20 through the line 3--3 of Fig. 2in which the device is shown at substantially its full size, and

Fig. 4 is ,a section on line d of Fig. l3.

Referring to the drawingand particularly to Fig. 3, the device consists of a's'traight piece of 25 tubing i which may be of substantially thei length and external shape indicated and having an inlet suction mouth ii and outlet exhaust mouth i2. Disposed near .the inlet mouth il 'of the tube is a compressed air jet y2li having an 30 orice 2| of predetermined area hereinafter def scribed, and which may befbevelledv slightly at its outlet end, `disposed in substantial alignment with the axis of the tube and directed toward the outlet end to cast aiine stream of compressedair 35 which is generally conical in form, longitudinally of the tube toward its outlet end. The internal periphery of the tube i 0 gradually converges from the jet for a predetermined distance, as shown at i3, toward the tube outlet end until it reaches the *40 mouth I5 of a4 shield commencing at the mouth and dened by the side wall i4 of the-tube which flares outwardly toward the outlet end of 'the tube at a predetermined divergent angle to be de- 5 scribed more in detail hereinafter.

The air jet 20 may4vv conveniently be'iormed in the shape of a tube, as indicated, closed at the bottom 22 and-screw threaded at its upper end to .be receivedfin the correspondingly screw threaded l substantially smaller in diameter than the duct 30 and having an enlarged head 36 closely but slidably fitting in the duct 30 and terminating in a nose 40. At the opposite end of the valve stem 35 from the nose 40 is a valve 4| seating on the valve seat 33,

Lengthwise movement of the valve stem 35 to open the valve 4| is effected bythumb lever 42 pivoted at 43 to the boss 24 and abutting the protruding nose 40 of the valve stem. Screw threaded into the open mouth of the chamber 32 is a tube l1 screw threaded at its protruding end to secure vthe coupling of a small rubber hose 68 (Fig. l) leading from the compressed air supply. Il preferably provide the valve chamber 32 with a fine mesh screen strainer of the shape indicated, for removing any extraneous matter that f may pass to the chamber from the air compressor.

The inlet mouthv l of the tube ll) may be provided with any suitable form of nozzle Gil (Fig. 1) and the outlet mouth l2 is received within a suitable dust bag S3 secured at one end to the tube as by the snap ring 62 in the groove 6l on the external periphery of the tube and closed at its opposite end with a sliding clamp 65. I'preferably also enclose the outlet mouth of the tube in a check valve 64 to prevent dust passing backwardly through the mouth l2 from the bag B3. The check valve may be in the form of an open ended sleeve, disposed within the bag G3 and secured about the outlet mouth by a snap ring 'i0 co-operating with a groove 'll on the surface of the tube.

One feature of my invention is the utilization of the compressed air supply to effect self .closing of the valve 4| and to that end the enlarged head 36 on the Valve stem 35- terminates in a shoulder 5|] which, when the valve .has been manually opened by depression of the thumb lever 42, is disposed in the position indicated at 50a in dotted lines in substantial alignment with one side of the vertical duct 23. As aresult ofthe relatively small size of the roriice 2|, hereinafter to be discussed in more detail, the back pressure in the ducts 23 and 30, when the Valve is open,v exerts a pressure against the shoulder 50 and against. valve 4|, thereby urgingv the Valve to closed position.

In' use, thetube 48 is connected to/"a compressed air supply which, in garages, is usually at a pressure of between one hundred and two hundrd pounds per square inch, or higher. The valve 4| is opened by depression of the lever 42 with the thumb and the compressed air owsthrough the ducts 3D and 23 to the orifice-2| which is considerably smallerin cross-sectional area than the ducts, thereby causing back pressure against the piston shoulder 50, now in the position at 50a, which urges valve 4| to closed position. Although the sizeof th jet orifijcemay be varied, I prefer to make it extremely small, such for example as between %4th of an inch and -ds or possibly 1/gth of an inch in-diameter, and

preferably about nlfd of an inch.

-The air, upon issuing from the ,minute orifice 2|, immediately expands somewhat and then assumes a general conical shape, aring at asmall stream flow unobstructed and 'at the aforemenv tioned small angle of divergence.

The flow continues in the general conical ilaring shape until the mouth I5 of the shield is reached and during the unshielded ilow of the air stream, suction is created in the tube and through the inlet mouth il thereof as a result of the entrainment or absorption of surrounding air.

The mouth l5 of the shield is of a cross-sectional area approximating, though possibly slightly less than, the cross-sectional area of the aring air stream at the mouth and the purpose of the shield and its mouth is not to restrict the stream to a smaller than normal cross-sectional area, but merely to enclose it at substantially its normal size and to shield it from surrounding air. The .radius of the mouth will approximate the sine of one-half the angle of divergence for the distance of the mouth from the orifice.

The specic size of the shield, and particularly its mouth l5, will of course vary, depending upon the angle o divergence of the stream and the distance of the mouth from the orifice 2|. The

` Velocity of the air stream at this point of initial enclosure is of importance as it determines directly, to a large degree, the amount of suction in inches of mercury produced by the stream. An excessive suction which may be produced by placing the mouth closer to the orifice and making it correspondingly smaller in size would, however, result in sacrlilce to the quantity of air drawn in and would produce an excessively high suction which would drop materially upon the intake of a substantial amount of cleaning air through the mouth ll. I therefore prefer to place the shield mouth at a substantial distance from the orifice 2|, and yet not at such an excessive distance as would reduce the suction force below that required. This distance of shield mouth from jetorice should be no less than one inch and should not exceed five inches and I have found thatv a distance of approximately 2% inches is preferable. Of course the siz of the mouth which approximates that of the stream at the mouth will vary asthls distance varies, and may be between about of an inch and '7/5 o f an inch in diameter and should be about 1%; of an inch if placed about 2% inches from the orifice.

`The shield continues from its inlet mouth I5 to the outlet end |2 of the tube in a aring shape, as indicated at I4, land with an angle of divergence whichl approximateabut may be slightly less than, the angle of divergence of the air stream entering the mouth. v

My inventionis. not, of course, to be limited to the details of construction or specific numerical values given above,l except as indicated in the appended claims and in those claims in which diameters are specified, I do not mean to limit myself to cross-sections which are circular in shape, although that is obviously" preferable, but I am lthereby merely defining areas relative to the varea of a circle of thel diameter'given.

1. In a vacuum cleaner, the combination of a conduit adapted to communicate with a supply 0i' compressed air. an orice in the conduit, no larger than one-eighth 'inch in diameter, adapted to eject an elongated, ilaring stream of air, a. shield to receive the air stream. so ejected,

enerally frusta-conical in shape and'conforming approximately to the size "andv shape o1' the air stream at the shield, means positining the shield with its axis in alinement with the, orifice and at a distance tromthe orifice to dispose the imaginary .apex o! the vshield approximately at the orifice,

, and a vmoiith in said shield to receive the air -to itsI entrance to the shield.

stream. spaced from the orice by a distance of 'its entrance to the shield. *l

larger than one-eighth inch in diameter, adapted to ejectanelongated. haring stream f air, a-

shield to receive 'the airstream so ejected, gen# rally frusta-amicalv in shape and conforming A 4'approximatelyto the size and shape of the airstream at the shield; means positioning the.'

of compressed air, an orifice in the conciitr no l shield with its axis in alin'exnent'fwith the orica'el andat a distancefrom the orifice to -dispose thel u l imaginary apei': of the shield -at or behind the orince, and a month in' said shield 5to. receive the` air stream, 'spaced fromthe orifice :by a distance of fromone to ilve inches whereby-to permit an uncontined flow ot the aring air stream prior tc mmm UNGENBRINK. 

